defconfigs: Migrate CONFIG_SYS_REDUNDAND_ENVIRONMENT

Move this symbol to Kconfig.  As part of this we can drop a UBI-specific
symbol that was a stop-gap for not having this particular symbol in
Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/MPC8349EMDS_SLAVE_defconfig b/configs/MPC8349EMDS_SLAVE_defconfig
index 7550aa3..c39c362 100644
--- a/configs/MPC8349EMDS_SLAVE_defconfig
+++ b/configs/MPC8349EMDS_SLAVE_defconfig
@@ -93,6 +93,7 @@
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_DATE=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y